auto-label.yaml

name: Auto Label PR

on:
  workflow_call:

jobs:
  auto-label:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4

      - name: Auto-label PR
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require('fs');

            const pr = context.payload.pull_request;
            const owner = context.repo.owner;
            const repo = context.repo.repo;
            const prNumber = pr.number;
            const body = pr.body || '';

            const LABEL_DEFS = {
              'needs:bump_db':       { color: 'd93f0b', description: 'PR references database repo changes' },
              'needs:bump_common':   { color: 'd93f0b', description: 'PR references common repo changes' },
              'needs:gomod_comment': { color: 'b60205', description: 'go.mod has uncommented local replace directives' },
              'type:bug':            { color: 'd73a4a', description: 'Bug Fixes' },
              'type:feature':        { color: '0e8a16', description: 'New Feature' },
              'type:breaking':       { color: '6f42c1', description: 'Breaking Change' },
            };

            async function ensureLabelExists(labelName) {
              try {
                await github.rest.issues.getLabel({ owner, repo, name: labelName });
              } catch (e) {
                if (e.status === 404) {
                  const def = LABEL_DEFS[labelName];
                  await github.rest.issues.createLabel({
                    owner,
                    repo,
                    name: labelName,
                    color: def.color,
                    description: def.description,
                  });
                  core.info(`Created label: ${labelName}`);
                } else {
                  throw e;
                }
              }
            }

            async function addLabel(labelName) {
              await ensureLabelExists(labelName);
              await github.rest.issues.addLabels({
                owner,
                repo,
                issue_number: prNumber,
                labels: [labelName],
              });
              core.info(`Added label: ${labelName}`);
            }

            async function removeLabel(labelName) {
              try {
                await github.rest.issues.removeLabel({
                  owner,
                  repo,
                  issue_number: prNumber,
                  name: labelName,
                });
                core.info(`Removed label: ${labelName}`);
              } catch (e) {
                if (e.status !== 404) throw e;
              }
            }

            const currentLabelsResp = await github.rest.issues.listLabelsOnIssue({
              owner,
              repo,
              issue_number: prNumber,
            });
            const currentLabels = new Set(currentLabelsResp.data.map(l => l.name));

            const labelsToAdd = new Set();
            const labelsToRemove = new Set();

            // needs:bump_db - PR body links to database repo
            const dbPattern = /(?:https?:\/\/github\.com\/TicketsBot-cloud\/database\/pull\/\d+|TicketsBot-cloud\/database#\d+)/i;
            if (dbPattern.test(body)) {
              labelsToAdd.add('needs:bump_db');
            }

            // needs:bump_common - PR body links to common repo
            const commonPattern = /(?:https?:\/\/github\.com\/TicketsBot-cloud\/common\/pull\/\d+|TicketsBot-cloud\/common#\d+)/i;
            if (commonPattern.test(body)) {
              labelsToAdd.add('needs:bump_common');
            }

            // needs:gomod_comment - uncommented local replace directives in go.mod
            try {
              const gomod = fs.readFileSync('go.mod', 'utf8');
              const replacePattern = /^replace\s+\S+\s+=>\s+\.\./m;
              if (replacePattern.test(gomod)) {
                labelsToAdd.add('needs:gomod_comment');
              } else if (currentLabels.has('needs:gomod_comment')) {
                labelsToRemove.add('needs:gomod_comment');
              }
            } catch {
              core.info('No go.mod found, skipping replace directive check');
            }

            // type:* labels - PR body checkboxes
            const typeChecks = [
              { pattern: /- \[x\] Bug fix/i,        label: 'type:bug' },
              { pattern: /- \[x\] New feature/i,     label: 'type:feature' },
              { pattern: /- \[x\] Breaking change/i, label: 'type:breaking' },
            ];

            for (const { pattern, label } of typeChecks) {
              if (pattern.test(body)) {
                labelsToAdd.add(label);
              } else if (currentLabels.has(label)) {
                labelsToRemove.add(label);
              }
            }

            for (const label of labelsToAdd) {
              if (!currentLabels.has(label)) {
                await addLabel(label);
              }
            }

            for (const label of labelsToRemove) {
              await removeLabel(label);
            }

            core.info('Auto-labelling complete');